help ar-15 build

i just did my 2nd kit build the 1st one was from Model 1 sales no problems

the new build was a dissipator from Delton

problem is that it always ejects but about 60% of the time it doesn't chamber a fresh round, i tried about 5 different kinds of ammo 3 different types of magazines, i switched bolts from another gun same thing happens

i called Delton this morning and they tell me because it is a dissipator i need to run hot rounds through the gun, this isn't an option i shoot often, i have 3 other ar carbines one rifle and an assortment of other guns that i shoot i normaly run the cheapest russian ammo i can lay my hands on only because i shoot sooooo much that any other way would just be to expensive

i need to find another fix, any ideas would be greatly appriciated, i came on this site because i have an x marine buddy that says that this is about the best forum that he has found and some one normally will have an idea for a fix

well if the bolt carrier key is not loose and staked like it should be, there is nothing lodged in the ring area or bent rings on the bolt. my next guess would be the gas system on the upper.

there could be an obstruction in the gas port area or gas line.

and it could also be that del-ton is a bit conservative with the gas port size.

i generally don't open up a port till i have eliminated all other suspects though.

if the bolt carrier and bolt looks OK and functions in another rifle you have pretty much narrowed it down to the gas system on the upper.

also be aware that some russian made ammo is a bit --how would we say this? er underpowered.

not to long ago i got a bunch of tula 223 from CTD that wouldn't function in anything for more that a couple rounds before it would fail to cycle the action.

so while your trying various things try a portion of the ammo in another rifle that you know works.

also double check the lower and run it for a few rounds on a running upper just to make sure everything it right with the lower and nothing is binding with it.

you would be shocked at how many times a bind in a buffer system or LPK will cause a short stroke like FTF!

if you have covered all the bases--then you can move on to the gas system. the "dissy" system most of them use the 20" gas system.

this is generally OK for full pressure rounds but if the port is standard 20" size it is likely to have problems with low pressure russian ammo.

also be aware that some "dissys" run 16" CAR type gas systems with a bolt on gas block that fits under the hand-guards. these are generally better for low pressure ammo as the CAR short gas system better matches the low pressure russian ammo.

the bolt on gas block can be a little off the port --this is an easy fix as you can just straighten up the gas port and block --re-tighten and it should start running.

the 20" will probably have a front sight base that is pinned on. the pins will have to be pressed off. some are very tight and some are tapered. seems like del-ton are tapered. once off i would check the port alignment and probably open it up one notch from whatever size del-ton drilled it.

1. I have noticed that some of the 1st and second tier manufacturers like Del-Ton tend to run their tolerances pretty tight. It just may be that you need to get 100 rounds of Factory .223 and go to town. I would do all of the checks that have been suggested first.

2. Gas rings. I have found that some bolts / bolt carriers have a bit of slop and can eat the gas rings in ways not immediately apparent. On my 3rd tier builds (Model1, Blackthorn) this was more prevalent, not sure it applies to you. The fix though, is to use a McFarland Ring. These are available from Armalite, and cost next to nothing.

To add to what J427x said:

1. Do check the clearances throughout the lower, and in the upper to lower lockup.
2. The only issue I have ever seen with the Dissy uppers is that they tend to allow pressure to fall off too fast, especially with lower power ammo like the russian stuff. This would fit the symptoms that you are describing. One fix is to use the old-Style Car-15 5.5 Inch flash suppressor. These are quite inexpensive, and can be installed without too much hassle.
Here is a link to the two products that I mentioned:

thank everyone for there suggestions i tried them all none worked, but i did find a fix Tula, is the most underpowered, next is Wolf, but i have found that the Brown Bear FMJ 55gr will cycle the gun, so i guess the one lesson i have learned through all of this is that out of all the crap ammo Brown Bear is the best, and truth be told i had always thought that Brown Bear was the worst just by the way they package the stuff

hockeydad.

I am an amateur with these things. But I asked questions and read up on how guys lube the bolt.
Lot of different suggestions as too lubing them.
But I put a fine film of Mil-Tech as suggested in this video. Seemed too make a good difference on the bolt going forward and picking up the rounds.

"Man needs but two things to survive alone in the woods. A blow up female doll and his trusty old AK-47" - Thomas Jefferson 1781

thank everyone for there suggestions i tried them all none worked, but i did find a fix Tula, is the most underpowered, next is Wolf, but i have found that the Brown Bear FMJ 55gr will cycle the gun, so i guess the one lesson i have learned through all of this is that out of all the crap ammo Brown Bear is the best, and truth be told i had always thought that Brown Bear was the worst just by the way they package the stuff

now that we know what page your on there are a couple things you can do about it.

the easy thing to do would be go to a lower pressure recoil spring.

that should let the dissy run with the wolf ammo.

if it was me i would also enlarge the gas port one size just to be on the safe side if you going to run mostly steel cased russian ammo.

now that we know what page your on there are a couple things you can do about it.

the easy thing to do would be go to a lower pressure recoil spring.

that should let the dissy run with the wolf ammo.

if it was me i would also enlarge the gas port one size just to be on the safe side if you going to run mostly steel cased russian ammo.

On several of my ar-15's I've had to open up the gas port- 1 size at a time!! When you get it to shoot Russian ammo it will shoot ANYTHING. Tula is the cheapest then Wolf and I like the Brown Bear but Golden Tiger is IMO the best of the cheap stuff. It also has a good muzzle blast for the Mall Ninjas with the shortys!! Ha Ha